Permalinks

I was able to modify the permalinks for my pages on my site from the “?pageid=123”..
to “wirelessonwater.com/store”.. but some of the pages have something like “wirelessonwater.com/about-us-4”..how do I remove the “us-4”..or extra text that is automatically being entered? I have changed it but it goes right back to adding the extra text. The only page besides the “home” page that is correct is “wirelessonwater.com/store”. It’s probably something simple..I’m just a little lost.

http://wirelessonwater.com

Thanks for your help!